Re: Clarification on two bits on VACUUM FULL VERBOSE output - Mailing list pgsql-performance

From Tom Lane
Subject Re: Clarification on two bits on VACUUM FULL VERBOSE output
Date
Msg-id 22587.1100294346@sss.pgh.pa.us
Whole thread Raw
In response to Re: Clarification on two bits on VACUUM FULL VERBOSE output  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
Josh Berkus <josh@agliodbs.com> writes:
>>> "There were 33076 unused item pointers."
>>> Is this a count of dead index pointers, or something else?
>>
>> No, it's currently-unused item pointers (a/k/a line pointers) on heap
>> pages. See http://developer.postgresql.org/docs/postgres/page.html

> So this would be a count of pointers whose items had already been moved?

Either deleted, or moved to another page during VACUUM FULL compaction.
Such a pointer can be recycled to point to a new item, if there's room
to put another item on its page ... but if not, the pointer is
wasted space.  I don't believe we ever try to physically eliminate
unused item pointers.

            regards, tom lane

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